Answer:
The answer for standard deviation would be:
4.382
So first calculate root of 3 which is 1.732
Next multiply by 8 to get 13.856
Hope this helps:)
3/4 just convert 1/2 to 2/4 and add 1/4
Reflecting a function across the x-axis means to change the sign of the function itself: you're mapping 
So, if you have a x/y values table, you simply have to change sign to all the values in the y column.
He worked a total of 405 minutes. Hope this helps!